The Drona Parva of the Mahabharata describes how Drona's son Ashwatthama, desperate to avenge his father's death, launched the Narayanastra, the illustrious weapon of Vishnu. The Narayanastra wreaked great havock on the Pandava army by making countless weapons rain down from the heavens, until Krishna told the secret of surviving it: laying down your own weapons and surrendering to its power. The Pandavas promptly did this, but out of arrogance Bhima refused and tried to fight against the Narayanastra. It was about to destroy him when Krishna and Arjuna forced Bhima to put down his weapons, at which point the Narayanastra was finally pacified.
But my question isn't about the story, but about the weapon itself. Here is how this Wikipedia page describes the Narayanastra:
When it was used, Ekadasha (Eleven) Rudras appeared in the sky to destroy Pandavas. Millions of types of weapons like Chakra, Gadha, ultra sharp arrows appeared in rage to destroy them.Who ever tried to offend were destroyed.
For those who don't know, the Rudras are a group of 11 Vedic gods associated with Shiva, as I discuss here and here. So my question is, is it true that the Narayanastra summons the Rudras to fight against your opponents?
I couldn't find such a claim in the Mahabharata; here is how the Drona Parva of the Mahabharata describes the effects of Ashwatthama using the Narayanastra:
Then Drona's son, aiming at the host of the Pandavas and the Panchalas, invoked the weapon called Narayana. Then thousands of arrows with blazing mouths appeared in the welkin, resembling snakes of fiery mouths, that continued to agitate the Pandavas. In that dreadful battle, those shafts, O king, like the very rays of the sun in a moment shrouded all the points of the compass, the welkin, and the troops. Innumerable iron balls also, O king, then appeared, like resplendent luminaries in the clear firmament. Sataghnis, some equipped with four and some with two wheels, and innumerable maces, and discs, with edges sharp as razor and resplendent like the sun, also appeared there. Beholding the welkin densely shrouded with those weapons, O bull of Bharata's race, the Pandavas, the Panchalas, and the Srinjayas, became exceedingly agitated. In all those places, O ruler of men, where the great car-warriors of the Pandavas contended in battle, that weapon became exceedingly powerful. Slaughtered by the Narayana weapon, as if consumed by a conflagration, the Pandava troops were exceedingly afflicted all over the field in that battle.
So it just describes weapons coming from the sky, not being launched by the Rudras. Vishnu describes the Narayanastra in similar terms to Ashwatthama in an earlier chapter of the Drona Parva:
With the aid of this weapon, thou too shalt pour diverse showers of celestial weapons in battle and blaze with energy in consequence of it.
So does anyone know if there are any scriptures that say that the Narayanastra summons the Rudras? And more importantly, if it is true then what is the reason for it? Why would a weapon of Vishnu summon gods associated with Shiva? If it's because Vishnu is the soul of the gods, then why would only the Rudras be summoned?